[Antimicrobial resistance and clinical significant resistance mechanisms of Salmonella isolated in 2014-2018 in St.Petersburg, Russia.]

The article presents the results of antimicrobial resistance monitoring of Salmonella isolated from children and adults with diarrhea in St. Petersburg in 2014-2018. In 746 isolates of 42 serovars more than 90,0% belonged to three: S. enteritidis (79,6%), S. typhimurium (6,8%) and S. infantis (3,8%). The antimicrobial susceptibility testing (according the EUCAST) to 7 classes of antimicrobials revealed the resistance in 78,6% of Salmonella. Low-level quinolone resistance (MIC of ciprofloxacin 0,12-0,5 mg/l) was detected in 63,3% isolates (S. enteritidis -71,0%, S. typhimurium - 15,7%, S. infantis - 89,3%) and was due to five kinds of single nucleotide substitutions in gyrA: Asp87Tyr - 36,1% of studied isolates (only S. infantis); Ser83Phe - 22,2% (only S. enteritidis); Asp87Asn - 19,4% (S. enteritidis, S. typhimurium, S. hadar, S. newport); Ser83Tyr -11,1% (S. enteritidis and S. infantis) and Asp87Gly - 8,3% (only S. enteritidis). Only in one S. kentucky isolate with high-level fluoroquinolone resistance (MIC of ciprofloxacin > 8,0 mg/l) two substitutions (Ser83Phe and Asp87Asn) were detected. Two Salmonella isolates (S. typhimurium and S. corvallis) had plasmid-mediated quinolone resistance (qnrS). Extended-spectrum cephalosporin resistance was found in 6 Salmonella serovars (1,6%). The bla-genes were detected: of genetic group CTX-M1 - in 10 isolates (serovars S. typhimurium, S. enteritidis, S. abony, S. coeln and S. virchow), CTX-M2 - in 2 S. typhimurium isolates, CTX-M9 - in three S. enteritidis isolates. In one S. typhimurium CTX-M1 and CTX-M2 were detected. The gene of CMY-2 (molecular class C cephalosporinase) was revealed in two isolates (S. newport and S. enteritidis). Our study showed that Salmonella (the main bacterial pathogen of acute diarrhea in children and adults) isolated in Saint-Petersburg had antimicrobial resistance to drugs of choice for salmonellosis treatment.

[Influence of various bacterial ligand application methods on cytokine expression].

AIM: Study the production of cytokines in mice during vaccination with polycomponent Immunovac-VP-4 vaccine containing TLR ligands with various administration methods. MATERIALS AND METHODS: Immunovac-VP-4 was administered to mice by subcutaneous, intranasal or per oral methods. The preparation was administered nasally at a single dose of 500 microg in the volume of 30 microl. Per oral single dose was 2000 microg in the volume of 0.5 ml. 200 microg of the preparation was administered subcutaneously. Cytokines in blood sera were determined by EIA 8 hours after the administration of the vaccine. RESULTS: In mice 8 hours afterthe single administration of Immunovac-VP-4 the levels of IL-1beta, IL-6, IL- 12, IL-5 increased significantly. However their concentration differed depending on the method of administration. The most active expression of cytokines was observed during subcutaneous administration. The indexes of cytokine expression were significantly higher (p < 0.05) than during non-parenteral administration methods. CONCLUSION: Mucosal application methods along with parenteral were established to be able to activate effector mechanisms of immune repose with its consequent polarization by Th1/Th2 pathways. These mechanisms lay the groundwork for development of antigen-specific immune responses against antigens/pathogens.